Southeast New York Stormwater Conference David R. Vallee Hydrologist-in-Charge NOAA/NWS Northeast River Forecast Center

Transcription

1 Southeast New York Stormwater Conference David R. Vallee Hydrologist-in-Charge NOAA/NWS Northeast River Forecast Center Record flooding along the Mohawk River in Rotterdam, NY, August 2011 following Irene. Photo from AP.

2 Part I: A bit about the Northeast River Forecast Center & how we go about the business of river and water resource forecasting Part II: Our changing climate Warm, wetter, more frequent extreme precipitation events, and changes in river flood frequency & magnitude Part III: New water resource services From hours to years From Summit to Sea / Tree Top to Bedrock

3 NOAA/NWS s Northeast River Forecast Center Our Mission: To provide our nation with river, flood and water resource forecasts for the protection of life and property and the enhancement of the national economy

4 WFO Caribou, ME Northeast Maine counties WFO Gray, ME Southwest Maine and all of New Hampshire WFO Burlington, VT Northern 2/3 rds of VT WFO Albany, NY Srn 1/3 of VT, Berkshire, MA, Litchfield, CT WFO Taunton, MA Rest of MA, all of RI, and the northern 2/3 rds of CT WFO Upton, NY All coastal CT Counties WFO Binghamton, NY Finger Lakes region WFO Buffalo, NY Buffalo Creeks, Genesee and Black

5 Watch/Warning responsibilities Coordinate final adjustments to RFC forecasts for warning issuances Issue and coordinate all watches/warnings with local interests Flood/Flash Flood Drought/Water Resource Hydrologic Outlooks Define forecast service requirements Establish flood stages and impact statements for forecast points Work with RFC on developing modeling requirements Provide Decision Support Services to the Decision Makers in the region

6 Calibrate and implement a variety of hydrologic and hydraulic models to provide: River flow and stage forecasts at 180 locations Guidance on the rainfall needed to produce Flash Flooding Ensemble streamflow predictions Ice Jam and Dam Break support Water Supply forecasts Partner with NOAA Line Offices to address issues relating to Hazard Resiliency, Water Resource Services, Ecosystem Health and Management, and Climate Change Moderate flooding - Connecticut River at Portland, CT.

7 From a Practitioner s Perspective Rainfall/Temperature trends Changes in flood & drought behavior Challenges going forward

8 Neither Ed nor I are climate scientists! We are practitioners We have the benefit of living in this part of the country i.e.: we are locals! It s different now beyond temps & precip Changes in vegetation, insects, bird life & river response Sea level rise The mission: Develop a better understanding of the current regime vs. the old & what that means to how we model our rivers Accumulation of Ingredients not one single source Where we are headed: that s the million $$ question!

9 Providence Street West Warwick, RI at 1030 am Wednesday 3/31/10

10 Record flooding along the Fish and Saint John Rivers northeast Maine, 4/30/2008 Providence Street Warwick, RI at 1030 am Wednesday 3/31/10 Home washed off its foundation on the Schoharie Creek, Prattsville, NY Tropical Storm Irene Record Flash Flooding in Utica, NY, July 1 st, 2017 Photo courtesy of Jill Reale (WKTV)

11 Several: Slow moving weather systems a blocked up atmosphere Multiple events in close succession or 1 or 2 slow movers Resulted in saturated antecedent conditions Each fed by a tropical connection Atmospheric Water Vapor Plumes of deep moisture

12 September Minimum Sea Ice Cover Arctic Sea Ice Summer Minimum This graph shows the average area covered by sea ice during September each year. Minimum sea ice extent has decreased 12% per decade since Data provided by the National Snow and Ice Data Center. Arctic sea ice concentration on the date of the 2016 minimum extent, September 10, NOAA Climate.gov image based on NOAA and NASA satellite data from NSIDC.

13 Modest changes in air & sea temperatures = atmosphere can hold more moisture The region is in close proximity to the ocean and the Gulf & Atlantic moisture streams Affected by dual storm tracks and blocking high pressure over Greenland These ingredients offer us more opportunities to latch onto these plumes Reduction of sea ice changes upper level wind flow Blocked up pattern induces slower moving storms or back-to-back-to back events L L H L

14 Common themes across New England: Increasing annual precipitation Increasing frequency of heavy rains Warming annual temperatures Wildly varying seasonal snowfall Shift in precipitation frequency (50, 100 yr 24 hr rain) For smaller (<800 sq mi) basins trend toward increased flood magnitude and/or frequency Most pronounced where significant land use change and/or urbanization has occurred Record flooding during Tropical Storm Irene, Catskills Region of NY. Photo: catskillstreams.org Record flash flooding, Islip, LI from 13 inches of rain. August 13 th, Photo: Ed Betz, Newsday

15 Hudson Valley The number of degrees that a day's average temperature is below 65 o Fahrenheit (18 o Celsius), the temperature below which buildings need to be heated The number of degrees that a day's average temperature is above 65 o Fahrenheit and people start to use air conditioning to cool their buildings

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17 Change in frequency of Heavy Precipitation Intense precipitation events (the heaviest 1%) Used to average 4-6 days a year of >1 of rain or more Today we are averaging nearly days! Source:

18 NOAA ATLAS Hour 100 year return period rainfall Much of southeast NY state has seen a 1-3 inch increase in the 24hr/100 yr storm! 7 7 Thick yellow lines represent 24 hr 100 yr values from TP-40,

19 >11

20 The Palmer Drought Severity Index (PDSI) uses readily available temperature and precipitation data to estimate relative dryness. It is a standardized index that spans -10 (dry) to +10 (wet). It has been reasonably successful at quantifying long-term drought. Since the late 60s, similar signature of much shorter, mostly less intense dry periods and longer higher amplitude wet periods

21 40 Deficit 20 Deficit

22 Number of Floods Per Year 1.2 Hudson River Basin Normalized Number of Minor, Moderate, and Major Floods Per Year Prior to 1970 Data provided by Major Floods Moderate Floods 1 Minor Floods NCKN6 RVRN6 HDYN6 HOPN6 WILM3 EAGN6 KASN6 LTLN6 PTVN6 BRTN6 COHN6 MTRN6 ROSN6 GRDN6 WAPN6 Location

23 Number of Floods Per Year 1.2 Hudson River Basin Normalized Number of Minor, Moderate, and Major Floods Per Year from Data provided by Major Floods 1 Moderate Floods Minor Floods NCKN6 RVRN6 HDYN6 HOPN6 WILM3 EAGN6 KASN6 LTLN6 PTVN6 BRTN6 COHN6 MTRN6 ROSN6 GRDN6 WAPN6 Location

24 Number of Floods Per Month Hudson River Basin Normalized Number Of Minor, Moderate, & Major Floods Per Month Prior to 1970 (15 Locations) Data provided by Major Floods Moderate Floods Minor Floods JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER Month

25 Number of Floods Per Month 0.35 Hudson River Basin Normalized Number Of Minor, Moderate, & Major Floods Per Month from (15 Locations) Data provided by 0.3 Major Floods Moderate Floods 0.25 Minor Floods JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER Month

26 The Northeast has become a hot spot for record floods & heavy rainfall in the past 10 years Noticeable trends include increased yearly rainfall and increased annual temperatures Portions of the Hudson valley have experienced a 1 to 3 inch shift upwards in the 100 yr 24 hour rainfall Smaller watersheds & those with significant urbanization are most vulnerable to increased river & stream flooding Drought episodes have become shorter in duration and of a Flash/Rapid Onset variety

27 Floodplain, land use, infrastructure, dam spillway requirements, drainage requirements, non-point source runoff, bridge clearances, hardening of critical facilities in the floodplain, property values etc Flood Insurance work to increase participation How much risk are we willing to insure and accept? Graphic courtesy of Cameron Wake University of New Hampshire

28 A Look At Future Water Prediction Services: Moving from Point Specific to Street Level Hydrologic Forecasting New services to include the Hydrologic Ensemble Prediction System & the new National Water Model Building a Weather-Ready Nation

29 NOAA National Water Model Implemented in August to provide foundation for sustained growth in nationally consistent operational hydro forecasting WRF-Hydro hydrologic core, community-based, ESMF compatible hydrologic modeling framework supported by NCAR Version 1.0 Goals: Focus on full range of water resources, provide streamflow guidance for underserved locations and spatially continuous national estimates and forecasts of hydrologic states, architecture that supports rapid infusion of new science and data NWM V1.0 System Flow 1/1. NWM Forcings Engine (NWS numerical weather models and observations) (avg. size ~1mi 2 ) 29

30 But it truly is a matter of scale Tomorrow s Scale 1 km or less! Prattsville Experimental simulation from the National Water Model Building a Weather-Ready Nation

31 NWM-Based Street Level Hydrologic Prediction Record Setting West Virginia Flood Event, June 23 rd 2016 Thousands of homes damaged or destroyed, $111+ million in FEMA aid NWM allows users to drill down from regional to local to street scale Information complements hydrologic guidance at existing forecast locations and provides new insight at millions of hydroblind locations NWM Street-Level Forecast Streamflow (cfs) Hydro-Blind location 500 people trapped at Elkview mall Bridge Collapse NWM 15 hr Regional Streamflow Anomaly Forecast, Valid 20Z 6/23 Experimental NWM Local Inundation Map Shading indicates flooded areas

32 Moving to probabilistic short to long range services AHPS short-range probabilistic product See: National Oceanic and Atmospheric Administration s National Weather Service 32 Northeast River Forecast Center Taunton, MA

33 Southeast New York Stormwater Conference David R. Vallee Hydrologist-in-Charge NOAA/NWS Northeast River Forecast Center Record flooding along the Mohawk River in Rotterdam, NY, August 2011 following Irene. Photo from AP.

34 1. The top 5 warmest years in southeast New York: Occurred prior to 1970 Occurred between 1990 and 2016 Are spread evenly across the last 100 years 2. Annual precipitation in southeast New York is: Decreasing at more than 1 inch per decade Increasing at a rate of about 1 inch every 17 years Staying exactly the same 3. Many rivers in the Hudson Valley are: Experiencing more frequent floods in the past 50 years Experiencing less frequent floods in the past 50 years 34

35 1. The top 5 warmest years in southeast New York: Have occurred prior to 1970 Have occurred between 1990 and 2016 Are spread evenly across the last 100 years 2. Annual precipitation in southeast New York is: Decreasing at more than 1 inch per decade Increasing at a rate of about 1 inch every 17 years Staying exactly the same 3. Many rivers in the Hudson Valley have: Experienced more frequent floods in the past 50 years Experienced less frequent floods in the past 50 years 35